As is commonly known, air conditioning systems in vehicles require charge valves. The charge valves, otherwise known as service valves, are employed in the air conditioning systems for testing, charging, discharging, and evacuating a refrigerant from the refrigeration system. It is desired for the charge valves to militate against leakage of the refrigerant and be readily opened for servicing. However, charge valves are commonly prone to undesired effects such as leakage, rapid deterioration, and/or inefficient operability due to contamination introduced to the charge valves during assembly processes. Typically, these undesired effects are the result of the arrangement of the components of the charge valve, the configuration of threaded portions of the charge valve, and inadequate sealing features.
For example, certain charge valves include a valve housing having an inner surface defining a cavity. A lower end of the valve housing is coupled to an air conditioning system component such as a refrigerant tubing, for example, to provide fluid communication between the air conditioning system and the valve housing. During assembly, a valve core is inserted through the cavity from an upper end of the valve housing opposite the lower end and threadingly engages the inner surface of the valve housing. The valve core includes a seal portion that engages the inner surface of the valve housing to selectively open and close the cavity. The seal portion is often formed at a lower end of the valve core and threads of the valve core are typically formed at an upper end of the valve core or above the seal portion. Disadvantageously, as the valve core threadingly engages the inner surface of the valve housing, contamination resulting from the threading action is formed. For example, the contamination can be burrs or particulates formed or loosened during the threading action. The contamination descends onto or adjacent to the seal portion, compromising a sealing of the cavity and resulting in the undesired effects.
Additionally, a brazing process is commonly used to couple the charge valve to the air conditioning system. However, undesired contamination such as excess flux, particulates, or debris resulting from the brazing process flow through the cavity from the lower end of the valve housing onto or adjacent the seal portion, compromising the sealing of the cavity and resulting in the undesired effects.
Furthermore, in another example, the charge valve may include an adaptor having a flow passage. The adaptor is typically pre-brazed to the air conditioning system component and then coupled to the charge valve to provide fluid communication between the air conditioning system and the charge valve. The adaptor includes internal threads that engage external threads of the valve housing of the charge valve. However, the contaminants from the brazing process flow through the flow passage and onto the internal threads and compromise sealing and engagement of the adaptor to the charge valve, resulting in the undesired effects.
It would therefore be desirable to provide a charge valve having a configuration minimizing the effects of contamination therein, wherein sealing, durability, and efficient operation is maximized.